GB204119A - Improvements relating to apparatus for wireless signalling and like purposes - Google Patents

Abstract

204,119. Onwood, A. June 21, 1922. Inductances.- The coupling between inductance coils in apparatus for wireless signalling and the like is varied by supporting one coil on a pivotal axis parallel to the plane faces of the coil and situated outside the space between these plane faces and on one side of the axis of the coil, so that the coil can be adjusted from a position beside and parallel to a fixed coil and in which the coupling between the two coils is maximum into a position in which the coupling is zero or negative, the centre of the moving coil moving away from the fixed coil during the adjustment. Three coils a - - c, may be removably mounted by plug- and-socket connections on insulating blocks f - - h, the block f being fixed on a shallow box d and the blocks g, h forming insulated arms pivoted at k, m and operated by handles n, o of sufficient length to avoid capacity effects of the operator's hand. The coils a - - c are connected to three pairs of terminals ,the connections of the coils b, c being through the pivots k, m and through spring brushes on the arms g, h co-operating with contacts r, s. The arms g, h are at 45‹ to the plane of the coils b, c and the pivots k, m are in a line with the outer edge of the coil a, or just within such line on the same side as the coil a, so that the coils b, c can be turned from positions parallel to the coil a and defined by stops q, through positions in which the coupling is zero and in which the coils b, c are at right angles to the coil a with their central planes passing through its axis, and into positions of small negative coupling defined by stops p. The angles between the arms g, h and coils b, c may be greater or less than 45‹, the movement from the maximum to zero coupling then being through less than or greater than 90‹ respectively. Coils of the kind disclosed in Specification 197,140 may be used. The coils a - - c may be respectively the tuning inductance of the closed secondary circuit of a wireless receiving apparatus, the aerial tuning inductance, and the reaction coil in the anode circuit of a thermionic valve. One fixed coil may co-operate with one moving coil, the two coils forming a variometer when connected in series or parallel.